The present invention relates to a video display apparatus for use with, for example, a multiscan monitor.
Currently there are monitors and television receivers which in addition to displaying an input video signal can display various adjustments and settings of the monitor by displaying characters, numerals, and graphics. This capability is called xe2x80x9con-screen displayxe2x80x9d and it permits the design of mechanically simpler video monitors and television receivers, thereby reducing their manufacturing costs and increasing their capabilities.
FIG. 1 of the accompanying drawings is a front view of a monitor illustrating a manner in which information is typically displayed on the display screen. As shown in FIG. 1, an information display area 18b (hereinafter xe2x80x9con-screen display portionxe2x80x9d) is displayed at a predetermined position of a display screen 18a and is used to display the current monitor settings by using characters, numerals, and graphics. In this example, the brightness setting of the display screen is displayed on the left side of the on-screen display portion and is indicated by the position of a pointer P in a bar graph along with corresponding numerals, and the contrast setting is displayed on the right side of the on-screen display portion also by the position of a pointer P in its corresponding bar graph along with corresponding numerals.
While these settings are being displayed on the display screen 18a, the user can change them at will by operating keys 31 to 34 installed on the monitor. When the displayed video image settings are adjusted, the corresponding graphs displayed on the on-screen display portion are changed to reflect the adjustments, thereby giving the user a visual feedback. Also, of course, the displayed video image on the display screen is changed to reflect the newly selected brightness and contrast settings. At the completion of the adjustment, the on-screen display portion is erased, ending the monitor adjustment mode and leaving on the display screen the adjusted video image. This adjustment method allows the user to make adjustments to the monitor with ease.
When the brightness of the display screen is adjusted, as described above, the brightness of the whole displayed image, including the on-screen display portion, is changed accordingly. In the case of an adjustment to make the display screen darker, the displayed images within the display screen are darkened and can become difficult to see. Therefore, when the user makes an adjustment to decrease the brightness of the display, the on-screen display portion gets darker and can become difficult to see.
In a television receiver, the brightness adjustment range is limited. Accordingly, even when the brightness of the image being displayed is adjusted to a minimum, the on-screen display portion is prevented from disappearing. On the other hand, in the case of a computer video monitor, such as a multiscan monitor, or a professional monitor, the brightness adjustment range is very wide. Therefore, when the brightness of the image being displayed is adjusted to a minimum the on-screen display portion becomes so dark that the displayed information cannot be seen.
Therefore, when the brightness is adjusted to the extent that the displayed image disappears or can barely be seen as described above, the user cannot make other adjustments because the on-screen display portion cannot be seen. This makes this desirable on-screen display feature ineffective and can lead the user to believe that the video monitor is malfunctioning.
It is an object of the present invention to provide a video display apparatus and a method for controlling the brightness of a display screen having an on-screen display portion in which the on-screen display can be satisfactorily perceived by the user regardless of the picture brightness.
This and other objects, advantages, and features of the present invention will become apparent to those skilled in the art upon consideration of the following description of the present invention.
According to one aspect of the present invention, a video display apparatus for controlling the brightness of a display screen having an on-screen display portion in which the on-screen display can be satisfactorily perceived by the user regardless of the picture brightness is provided with: a display screen; circuitry for displaying on the display screen an on-screen display portion showing adjustment data for the video display apparatus; and circuitry for maintaining the brightness of the on-screen display portion substantially constant while the brightness of the display screen is changed.
According to a second aspect of the present invention, a method for controlling the brightness of a display screen of a video display apparatus having an on-screen display portion is provided that consists of controlling the brightness of the display screen while maintaining the brightness of the on-screen display portion substantially constant.
According to the above described aspects of the present invention, because the brightness of the on-screen display portion is kept substantially constant regardless of the brightness of the display screen, the user can properly be guided through the video display adjustment process by reading the instructions on the on-screen display portion.